<!DOCTYPE html>
<html lang="en" xmlns:v-on="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="UTF-8">
    <title>03demo</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>

<div id="app">
    <span v-text="message">Test Hello</span>
    <span v-html="message">Test Hello</span>
</div>
<script type = "text/javascript">
    var app=new Vue({
         el:"#app",
        data:{
             message:"<h1>Hello vue</h1>"
        },

    })
</script>
</body>
</html>